Cooling system for transformers



April 22, 1947. COOK 2,419,439

COOLING SYSTEM FOR TRANSF RMERS Filed Jan. 51, 1944 4 Sheets-Sheet 1 INVENTOR.

RALPH H. COOK 'BYE',

ATTORNEYS April 22, 1947. w R. H. cooK 2,419,439

COOLING SYSTEM FOR TRANSFORMERS Filed Jan. 51, 1944 4 Sheets-Shet 2 Q can -2: ::*';7'- ""11 I O F i' 1 l h I I I l I l I u I I I] I: II h 1 II Q 1 'I l I [I H I H I "1| ll H I] h I l 1 II |l II l H H h II I 'I I I l v I I H I'J I I I I I 9 I] II I I I l 1| n l 1' I |I I l 1| 'l n I i I. H i l I] ll 11 I I H I: ll 1 l I ll H l Jun I H Q I I J a H INVENTOR. RALPH H. COOK FIGZ.

ATTORNEYS April 22, 1947. COOK 2,419,439

COOLING SYSTEM [FOR TRANSFORMERS Filed Jan. 31, 1944 4 Sheets-Sheet 3 INVENTOR.

RALPH H .COOK

M QRNEYS April 22, 1947. O 2,419,439

COOLING SYSTEM FOR TRANSFORMERS Filed Jan. 31, 1944 4 Sheets-Sheet 4 IFIG.5.

I -,u ,l. g 7 INVENTOR.

. 7 RALPH H.COOK

ATTORNEYS Patented Apr. 22, 1947 UNITED STATES PATENT OFFICE 7 Claims.

The invention relates to cooling system for transformers and refers more particularly to cooling systems for transformers which are immersed in a coolant, such as oil.

The invention has for ome of its objects to provide an improved system for economically cooling a transformer; to provide an improved transformer cooling system which comprises power means for propelling the coolant, the power means being operable only when the load on the transformer exceeds a predetermined value, whichis in economical keeping with the rating of the transformer; to provide an improved transformer cooling system in which the coolant propelling power means does not appreciably interfere with or affect the normal flow of the coolant responsive to normal thermal action when the load on the transformer is below the above mentioned predetermined value; to provide an improved transformer cooling system in which the movement of the coolant between the transformer and the cooling means, such as radiators, tubes, or fins for dissipating heat present in the coolant, is free or unconfined or unrestricted as by ducts, baflles, pipes and the like, heretofore used to direct the flow of the coolant, whereby economical cooling is attained; to provide an improved transformer cooling system wherein the desired electrical clearances may be readily provided because of the absence 'of ducts, pipes, baflies and the like, reducing said clearances.

The invention has for other objects to provide an improved transformer cooling system in which the coolant is moved at substantially uniform Velocity through the tank containing the coolant thereby maintaining a temperature throughout the device which is relatively constant and uniform; to provide an improved transformer cooling system wherein the movement of the coolant is generally tangential to the electrical windings of the transformer; and to provide an improved transformer cooling system in which the movement of the coolant is generally longitudinal of the means for conducting the cooling medium and the coolant keeps the surface of the conducting means free of deposit so that maximum heat transfer may be secured.

The invention has for further objects to provide an improved transformer cooling system in which the power means propels the coolant in a direction transverse to the normal flow of the coolant and, more particularly, the power means propels the coolant generally horizontally while the normal flow of the coolant in response to the normal thermal action is generally vertical; and to provide an improved transformer cooling system for a core type transformer in which the direction of movement of the coolant is such that flow of the coolant in the transformer pockets, which are of relatively short height, takes place to thereby more effectively transmit the heat from the transformer.

These and other objects of the invention will become apparent from the following description, taken in connection with the accompanying drawings, in which Figure 1 is a top plan view, partly broken away and with the cover removed, of a transformer and cooling system therefor embodying the in vention;

Figure 2 is a side elevation thereof, partly broken away;

Figure 3 is a View similar to Figure 1 illustrating another embodiment of the invention;

Figure 4 is a ide elevation, partly broken away, of Figure 3;

Figure 5 is a View similar to Figure 1 illustrating another embodiment of the invention;

Figure 6 is a side elevation, partly broken away, of Figure 5.

Referring to Figures 1 and 2, I is a tank containing a coolant, such as cooling and insulating oil, and 2 is a transformer within the tank and immersed in the coolant. The upright wall of the tank is preferably formed at its upper edge with the flange 3 to which is secured the tank cover. As illustrated, the transformer is of the three-winding, three-phase core type having the upright stacks 4 of vertically spaced horizontal electrical windings 5, the upright cores 6 extending through the windings, and the upper and lower frame members I and 8, respectively. The

windings of each stack are spaced by the radialspacers 9 which with the windings and associated core form horizontal pockets opening radially outwardly, the opening being of relatively short height and of relatively great horizontal length. The upright wall of the tank has the arcuate ends III which are concentric with the end cores 1 and the end winding stacks 5 and the parallel sides II which connect tangentially into the arcuate ends and are parallel to the plane passing through the axes of the cores and winding stacks.

For conducting a cooling medium to cool the oil, there are the water tubes l2 coiled within the tank and spaced from and substantially conforming to the contour of the upright wall of the tank. The tubes, as shown, are arranged in a double row and have the inlets I3 and the outlets 14, each tube being endles between its inlet and outlet and having a relatively large number of substantially horizontal coils. It is to be noted that the space between the winding stacks and the tubes is continuous and unobstructed and this space, as illustrated, is greater than the space between the upright wall of the tank and the tubes.

The construction is such that the normal flow of the coolant responsive to normal thermal action of the transformer is generally vertical, the coolant passing upwardly over the electrical windings of the stacks and downwardly over the tubes. Also the construction is such that the normal flow of the coolant is free or unconfined or unrestricted because the space in which the normal flow takes place is continuous and contains no obstructions, such as ducts, ba-files, pipes, and the like. Furthermore, because the space is continuous and clear throughout, the desired electrical clearances may be readily secured.

To commercially increase the capacity of the transformer, I have provided power means for propelling the oil so that it will transmit heat from the electrical windings to the water which is being circulated in the cooling tubes l2. In the present instance, the power propelling means comprises the propellers 15, each of which is driven by an electric motor IS. The propellers are positioned below the tubes 12 and laterally outwardly of the vertical plane of the laterally inner sides or" the coils of the laterally inner tube. Each electric motor is end mounted on the plate I! which is fastened in an oil-tight manner by the bolts iii to the flange IS at the outer end of the housing 20 within which the motor and its associated propeller are located. The housing is fixedly secured to the upright wall of the tank I and, as shown in the present instance, the housing is welded to the upright wall, the latter being formed with an opening registering with the interior of the housing. As shown in the present instance, four power-propelling means are employed with two at each side I l of the upright wall of the tank. Each is mounted so that its axis extends substantially at a horizontal plane angle of 45 to the side H and also at a vertical plane angle or" substantially 10 to the side H. The inclinations of all of the power propelling means are the same so that the oil is circulated in a clockwise direction generally horizontally, but slightly upwardly, so that after the power propelling means have been running for a time the whole body of oil from the bottom to the top circulates generally horizontally.

The construction is such that the power means for propelling the oil does not appreciably interfere with the normal flow of the oil responsive to normal thermal action o that as a result the power propelling means need only be used when the load on the transformer exceeds a predetermined value which in economical keeping with the rating of the transformer. Also, the arrangement is such that the oil is moved with substantially uniform velocity through he tank so that relatively constant and uniform temperature throughout the device may be secured. Also during the major portion of the circulation of the oil it flows generally tangentially of the electrical windings so that by reason of its impact upon the radial spacers and also by reason of eddies set up in the pockets formed between the electrical windings, how of oil takes place in these pockets to conduct way the heat generated in the electrical windings and thereby lower their temperature. Furthermore, the oil being circulated moves longitudinally of the water tubes and has a sufficiently brisk action to remove any deposit, such as thickened oil on the tubes. As a result, heat is most efliciently conducted from the oil to the water in the tubes.

Figures 3 and 4 illustrate another embodiment of the invention in which 21 is the tank and 22 the transformer within the tank and immersed in the cooling and insulating oil forming the coolant. The transformer is of the same construction as the transformer 2. The tank 2| is also of generally the same construction as the tank I of Figures 1 and 2, but the tank 2| differs in having the sides of its upright wall formed with the upright generally semi-cylindrical bosses 23. The power means for propelling the oil in this modification has the propellers 24 of the paddle-wheel type having generally vertical shafts, the lower ends of which are connected to the shafts of the electric motors 25, both the paddle wheels and the electric motors extending within the bosses The upper ends of the propeller shafts are adjustably mounted in the upper walls of the bosses to provide for alignment of the propeller shafts with the motor shafts. There is but one power propelling means at each side and it is preferably located opposite the space between a center and an end winding stack, the power propelling means at one side being oiiset along the major axis of the transformer relative to the power propelling means at the other side. The water tubes 28 and 2'1, instead of extending continuously around the upright wall of the tank, extend from adjacent one power propelling means to adjacent the other power propelling means. As shown, each tube has an inlet and an outlet through an arcuate end wall of the tank and comprises a series of loops extending to the power propelling means. The cooling system functions practically the same manner as that of Figures 1 and 2.

Figures 5 and 6 illustrates another embodiment of the invention in which the heat present in the coolant is dissipated by means cooled by air, instead of water. More particularly, 28 is the'transformer of the same construction as the transformer i, an 29 is the tank containing the coolant in which the transformer is immersed. 30 are the power means for propelling the coolant, the power means being the same or substantially the same and being arranged in the same manner as the power means of Figures 1 and 2. The tank is designedly formed into a radiator externally exto air which may flow in response to normal thermal action or which may be suitably power prop d. As shown in the present instance, the t is vertically corrugated to form the hollow fins 3i, except in the areas of the power means Flow of the coolant in the hollow fins takes place in the same manner as in the pockets formed between the electrical windin The cooling system functions in much the e manner as that of Figures 1 and 2.

is be noted that the cooling system is equally applicable to existent and new design transformers and does not require installation of additional devices which in any way reduce the original el ical or coolant clearances and does not appreciably increase the overall size of a complete transformer having the clearances prevalent in good design. Also the power propelling means and cooling tubes form parts of a self-contained fully enclosed system which eliminates the necessity of troublesome sealing means,

such as packing boxes. Furthermore, the system is economically applicable to all designs of transformers.

What I claim as my invention is:

1. The combination with a tank, a core type transformer having radially outwardly opening horizontal pockets between the electrical windings and water tubes having substantially horizontal portions extending around and spaced from said transformer, said transformer and tubes being immersed in oil within said tank, of means for propelling the oil generally horizontally and creating a flow around said transformer and in said pockets of said transformer and along said tubes.

2. The combination with a tank, a transformer having electrical windings immersed in oil within said tank and spaced from a wall of said tank, and water tubes also immersed in oil within said tank and spaced from said windings and also spaced from said wall of said tank, of means substantially out of the path of the normal ficw of the oil for propelling the oil generally transversely of the normal flow or the oil and past said windings and water tubes.

3. The combination with a tank, a core-type transformer having radially outwardly opening horizontal pockets between the electrical windings, and cooling medium conducting tubes hav ing substantially horizontal portions extending around and spaced from said windings, said windings and tubes being immersed in a coolant within said tank, of means substantially out of the path of the normal flow of the coolant within said tank for propelling the coolant generally horizontally and creating a flow around said windings and in said pockets and along said tubes.

4. The combination with a tank, a transformer having electrical windings and cooling medium conducting means, said windings and means being immersed in a coolant within said tank and providing an unobstructed space for normal upward flow of the coolant past said windings and normal downward flow of the coolant past said means for the normal cooling of said transformer, of power means for propelling and circulating the coolant in the space generally horizontally around said windings and along said means.

5. The combination with a tank, a transformer having electrical windings and cooling medium conducting means, said windings and means being immersed in a coolant within said tank and providing an unobstructed space for normal upward flow of the coolant past said windings and normal downward flow of the coolant past said means for the normal cooling of said transformer, of power means substantially out of the path of the normal upward flow of the coolant for propelling and circulating the coolant in the space generally horizontally around said windings and along said means.

6. The combination with a tank and a transformer having electrical windings immersed in a coolant within the tank, said windings being spaced from the tank wall to provide space for normal upward flow of the coolant past said windings and normal downward flow of the coolant past the tank wall, of power means for propelling the coolant generally horizontally toward the windings, said power means being mounted on the tank wall and creating a flow of the coolant along the interior of the tank wall and around the transformer.

7. The combination with a tank and a transformer having electrical windings immersed in a coolant within the tank, said windings being spaced from the tank wall to provide space for normal upward flow of the coolant past said windings and normal downward flow of the coolant past the tank wall, of power means for propelling the coolant generally horizontally toward the windings, said power means comprising a propeller and an electric motor for driving said propeller and being mounted on the r tank wall with the axis of the propeller inclined at a horizontal plane angle and a vertical plane angle to the wall and creating a flow of the coolant along the interior of the tank wall and around the transformer.

RALPH H. COOK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,083,945 Randall Jan. 13, 1914 2,024,742 Parsons Dec. 17, 1935 2,125,138 Vogel July 26, 1938 

